An engine installed in a vehicle is controlled by various data input for driving the engine.
As shown in FIG. 1, an intake pipe 11 through which outside air flows into an engine 1 is provided with a compressor 22 of a turbocharger for compressing intake air, an intercooler 23 for cooling the compressed air and a throttle valve 21 for controlling amount of the air flowing into the engine; an exhaust pipe 12 through which exhaust gas burned in the engine 1 is discharged is provided with a turbine 41 of the turbocharger rotated by the exhaust gas, various post-processing devices and the like; and an exhaust gas recirculation (EGR) line 13 for recirculation of the exhaust gas has an EGR valve 51, an EGR cooler 51 and the like.
In addition, the engine 1 is controlled by acquiring information on the intake air flowing into the engine 1 through a hot-film air mass flow sensor (HFM) 31 provided at an inlet of the intake pipe 11 to measure temperature and amount of the intake air, a boost pressure sensor 32 installed between the compressor 22 and the throttle valve 21 to measure pressure boosted by turbo operation, and a manifold absolute pressure (MAP) sensor 33 for measuring pressure in the intake manifold 11a and taking into consideration of an operation amount of an accelerator pedal operated by a driver and the like.
Such an engine is manufactured so as to generate output within a predetermined range.
However, some drivers often install an arbitrary tampering device or a defeat device which is intended to tamper a part of input data for driving the engine and generate output greater than that within the range set at the time of manufacturing the engine.
For example, as shown in FIG. 2, a defeat device 70 is installed between the boost pressure sensor 32 and an engine management system (EMS) 60 to raise output of the engine 1 by tampering or falsifying signals output from the boost pressure sensor 32. The defeat device 70 raises output of the engine 1 by lowering an output value of the boost pressure sensor 32 and inputting it to the EMS 60. Here, the EMS 60 may be an electronic control unit (ECU) or integrated with the ECU.
When receiving boost pressure lower than actual pressure, the EMS 60 calculates flow rate passing through the throttle to be smaller than actual flow rate. When calculating the modeled pressure of the intake manifold, flow rate flowing into the intake manifold and flow rate discharging from the intake manifold (flow rate flowing into cylinders) are calculated to be the same. If the defeat device 70 is installed, input flow rate becomes greater than output flow rate, i.e., “input flow rate>output flow rate” so that the modeled pressure is raised and hence output of the engine 1 is enhanced.
However, if the output of the engine 1 is tampered arbitrarily so as to be raised, parts of the engine are damaged or a turbo actuator is damaged due to knocking, pre-ignition and the like. The engine 1 is generally manufactured to have mechanical strength and durability in consideration of a predetermined output. However, if the output of the engine is raised arbitrarily, the engine 1 is damaged, which may cause a serious accident.
Nonetheless, if a driver installs the defeat device 70 to raise output of the engine 1 during using the vehicle and removes the defeat device 70 only at the time when the vehicle is repaired or inspected, there is a problem that when the engine 1 is failed, cause of the failure cannot be find out precisely and hence it cannot cope with the failure properly.